Re: Ipac cradle not charging fully via USB?

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From: AshleyJ (news_at_ashleyj.co.uk)
Date: 02/03/05 

Date: Thu, 03 Feb 2005 20:32:02 +0000

Beverly Howard [Ms-MVP/MobileDev] wrote:

> Note that most cradles _do not charge from the activesync connection_.
> You should check the specifications of the cable/cradle to see if usb
> charging is claimed. If this is the case, the "increase" you are seeing
> may just be battery recovery voltage from being turned off overnight.
>
> The reason for this is that certified usb devices (such as oem
> equipment) must specify the amount of power they demand from the usb
> port, so, most oems claim signal power only and provide charging power
> through the cradle from a separate charging adapter... if the charger is
> not connected to the cradle, the unit will sync but not charge.
>
> A number of aftermarket usb "charging cables" have been on the market
> for the past couple of years because they don't have to meet this
> specification... the cables have no usb id's and, therefore don't have
> to report their power demand to the host. If they claim charging
> capability, you should be getting a charge subject to the following.
>
> Additionally, usb ports have different power capacities depending on
> their capabilities plus the number of other devices connected to the
> port... when power demand exceeds what the host can provide, the power
> section of the port simply shuts down.
>
> In some cases, where all devices correctly report their power demand,
> you may receive a power demand error message, but, in my experience,
> this occurs only in cases where attached devices listed demands exceed
> the host's specification capacity.
>
> HTH,
> Beverly Howard [MS MVP-Mobile Devices]

Very true.
I have an iPAQ hx4700 which will sync but not charge using the HP cradle
but I have purchased a charge/sync cable which is a lot more convenient
to use and this charges the iPAQ battery very quickly, typically from
around 80% to full charge in just over a hour.

Ash

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